【摘要】 用红外CO2 分析仪和叶绿素荧光仪测定了温州蜜柑和脐橙叶片的净光合速率 (Pn)、初始荧光(Fo)、最大光能转换效率 (Fv/Fm)及电子传递速率 (ETR) .结果表明 ,与常温 (2 5℃ )相比 ,高温胁迫 (38～ 4 0℃ )使温州蜜柑和脐橙叶片的Pn、Fv/Fm及ETR下降 ,Fo升高 .胁迫 2 5d后温州蜜柑和脐橙叶片的Pn分别下降 5 5 .6 %和 39.8% ,Fv/Fm下降 2 2 .0 %和 6 .7% ,ETR下降 5 5 .0 %和 4 1.5 % ,Fo分别上升了 113.8%和 14 .9% .柑橘经高温胁迫后 ,在 2 5℃下处理 10d ,叶片的Pn、Fv/Fm、Fo及ETR恢复明显 .这些结果说明柑橘的光合速率下降与PSⅡ反应中心失活有关 .更多还原

【Abstract】 Table ADC 225 MK3 CO 2 gas analyzer and PAM 2000 portable fluorescence measurement system were used to measure the net photosynthetic rate ( Pn ), initial fluorescence ( Fo ), maximal photochemical efficiency of PSⅡ ( Fv/Fm ) and electron transport rate ( ETR ) of satsuma mandarin ( Citrus unshiu Marc.) and navel orange ( C. sinensis Osbeck ) leaves. The results showed that exposure of citrus plants to high temperature (38～40 ℃) led to a lowering of Pn , Fv/Fm , and ETR , whereas Fo increased. After exposure to high temperature for 25 days, compared with normal temperature (25 ℃),the Pn of satsuma mandarin and navel orange leaves decreased by 55.6% and 39.8%, Fv/Fm decreased by 22.0% and 6.7% and ETR reduced by 55.0% and 41.5 %, respectively. On the other hand, Fo increased 113.8% and 14.9%,respectively. With subsequent transfer to the 25 ℃ culture room for 10 days, Pn , Fv/Fm , Fo and ETR recovered significantly. These results demonstrated that the reduction of Pn in Citrus was related to the inactivation of PSⅡ reaction center.更多还原